I burned my sub and Need help to choose Other!!! urgently!

i recent buy a single diamond audio d3 sub and i put this sub in prefab box (stup!d cheap box) with my rockford p300.1 amp

i have 2 weeks with the sub and i burned this today when adjusted the amp frequency , i guess was the box measures are not correct

I think buy a new subwoofer morning

i have 80 dolars for a single sub, in a local shop offerts me this options:

Single Crunch GPV12D4 600 RMS for $75 bucks (equivalent because i live in dominican rep)
Single PIONEER CHAMPION TS-W309D4/TS-W308D4 for $85
2X HiFonics HFi12D4 for only $72
Pioneer Champion 10'' used for $30 LOL

p.d: i have another amp tired in my house, an HiFonics BXI1205D, and now i fabric the correct box because before i no have time and buy this sh!tty box

Re: I burned my sub and Need help to choose Other!!! urgently!

i find other option and more expensive, is Rockford fosgate P2?, in the have all size's, 10's, 12's, 15's, is this option any good?, what size is the best for my civic EG HB 1995?, (two 10's, single 12 or single 15?)